Initially designated Category Four, Michael was upgraded Friday to Category Five after the National Oceanic and Atmospheric Association found that its winds neared 160mph. Assessing a hurricane's top wind speeds quickly via weather stations is hard because the stations are often damaged during harsh storms, per the Weather Network.

Before Michael, the last Category Five storm to strike America was Andrew in 1992. (See what happened to 284 people who rode out Michael in a Florida city.)